Author Contributions
C.S. conceptualised the research work, conducted experimental design, data analysis, data curation and wrote the original draft. J.M. and B.P. conducted computed tomography experimental design, data analysis. S.S. conducted experimental design, data curation, data analysis, and proofread the final draft. G.S. supervised, proofread the final draft, and provided comments for improving the manuscript. J.S. supervised, proofread the final draft and provided comments for improving the manuscript. All authors have read and agreed to the published version of the manuscript.
Figure 1.
MEX and CFC print head photography and schematics of Composer A4 CFC print head. The photography shows two print heads, a typical MEX print head for plastic printing (red box) and a CFC print head (purple box) for composite printing.
Figure 1.
MEX and CFC print head photography and schematics of Composer A4 CFC print head. The photography shows two print heads, a typical MEX print head for plastic printing (red box) and a CFC print head (purple box) for composite printing.
Figure 2.
Graphical representation of part configuration generated via slicing software. Black coloured lines are outer thermoplastic perimeters, green coloured line represents micro infill thermoplastic filling by MEX print head, and orange and blue series lines are CCF reinforced perimeter and infill by CFC print head. The purple pointed arrow shows the direction of CCF printing and the pattern “x” marks the symbolic fibre cut operation.
Figure 2.
Graphical representation of part configuration generated via slicing software. Black coloured lines are outer thermoplastic perimeters, green coloured line represents micro infill thermoplastic filling by MEX print head, and orange and blue series lines are CCF reinforced perimeter and infill by CFC print head. The purple pointed arrow shows the direction of CCF printing and the pattern “x” marks the symbolic fibre cut operation.
Figure 3.
Top midsection CT images (X-Y) of the N-PLA with corresponding side midsection inset views (X-Z). A black circle is indicative of voids due to the thermoplastic matrix and red arrows showed voids within the CFC processed CCF.
Figure 3.
Top midsection CT images (X-Y) of the N-PLA with corresponding side midsection inset views (X-Z). A black circle is indicative of voids due to the thermoplastic matrix and red arrows showed voids within the CFC processed CCF.
Figure 4.
Tensile tested fractured image (a) and CT image (X-Y) (b) of L-PA6-CFC specimen. The longitudinal failure observed in the tensile tested image (a) is due to the defects observed in the CT image is indicated by arrows connected to the defective region (red box) in CT-scanned image (b).
Figure 4.
Tensile tested fractured image (a) and CT image (X-Y) (b) of L-PA6-CFC specimen. The longitudinal failure observed in the tensile tested image (a) is due to the defects observed in the CT image is indicated by arrows connected to the defective region (red box) in CT-scanned image (b).
Figure 5.
Tensile test data of PLA with a corresponding error bar. Where, N-PLA is neat PLA and S-PLA is short carbon fibre filled PLA. The corresponding IM, MEX-0°, and CFC are injection moulded, 3D printed and composite filament co-extruded 3D printed tensile tested specimens, respectively.
Figure 5.
Tensile test data of PLA with a corresponding error bar. Where, N-PLA is neat PLA and S-PLA is short carbon fibre filled PLA. The corresponding IM, MEX-0°, and CFC are injection moulded, 3D printed and composite filament co-extruded 3D printed tensile tested specimens, respectively.
Figure 6.
Tensile test data of PA6 with a corresponding error bar. Where, N-PA6 is neat PA6 and L PA6 is long carbon fibre reinforced PA6. The corresponding IM, MEX-0°, and CFC are injection moulded, 3D printed and composite filament co-extruded 3D printed tensile tested specimens, respectively.
Figure 6.
Tensile test data of PA6 with a corresponding error bar. Where, N-PA6 is neat PA6 and L PA6 is long carbon fibre reinforced PA6. The corresponding IM, MEX-0°, and CFC are injection moulded, 3D printed and composite filament co-extruded 3D printed tensile tested specimens, respectively.
Figure 7.
Flexural test data of PLA with a corresponding error bar. Where, N-PLA is neat PLA and S-PLA is short carbon fibre filled PLA. The corresponding IM, MEX-0°, CFC, and CFC-PC are injection moulded, 3D printed, composite filament co-extruded, and post-processed composite filament co-extruded 3D printed 4-pointing beding tested specimens, respectively.
Figure 7.
Flexural test data of PLA with a corresponding error bar. Where, N-PLA is neat PLA and S-PLA is short carbon fibre filled PLA. The corresponding IM, MEX-0°, CFC, and CFC-PC are injection moulded, 3D printed, composite filament co-extruded, and post-processed composite filament co-extruded 3D printed 4-pointing beding tested specimens, respectively.
Figure 8.
Flexural test data of PA6 with a corresponding error bar. Where, N-PA6 is neat PA6 and L PA6 is long carbon fibre reinforced PA6. The corresponding IM, MEX-0°, CFC, and CFC-PC are injection moulded, 3D printed, composite filament co-extruded, and post-processed composite filament co-extruded 3D printed 4-pointing beding tested specimens, respectively.
Figure 8.
Flexural test data of PA6 with a corresponding error bar. Where, N-PA6 is neat PA6 and L PA6 is long carbon fibre reinforced PA6. The corresponding IM, MEX-0°, CFC, and CFC-PC are injection moulded, 3D printed, composite filament co-extruded, and post-processed composite filament co-extruded 3D printed 4-pointing beding tested specimens, respectively.
Figure 9.
Specimen Nr. 3 of N-PA6-CFC showing delamination (a) and specimen Nr. 2 of N-PA6-CFC-PC showing buckling with little delamination at failure (b).
Figure 9.
Specimen Nr. 3 of N-PA6-CFC showing delamination (a) and specimen Nr. 2 of N-PA6-CFC-PC showing buckling with little delamination at failure (b).
Table 1.
Material nomenclature.
Table 1.
Material nomenclature.
Material Description | Nomenclature |
---|
Neat PLA | N-PLA |
Injection-moulded neat PLA | N-PLA-IM |
Neat PLA material extruded with a raster angle of 0° | N-PLA-MEX-0° |
Neat PLA as a binding matrix in CFC | N-PLA-CFC |
Post-consolidated neat PLA as a binding matrix in CFC | N-PLA-CFC-PC |
Short carbon fibre-filled PLA | S-PLA |
Injection-moulded short carbon fibre-filled PLA | S-PLA-IM |
Short carbon fibre-filled PLA material extruded with a raster angle of 0° | S-PLA-MEX-0° |
Short carbon fibre-filled PLA as a binding matrix in CFC | S-PLA-CFC |
Post-consolidated short carbon fibre-filled PLA as a binding matrix in CFC | S-PLA-CFC-PC |
Neat PA6 | N-PA6 |
Injection-moulded neat PA6 | N-PA6-IM |
Neat PA6 material extruded with a raster angle of 0° | N-PA6-MEX-0° |
Neat PA6 as a binding matrix in CFC | N-PA6-CFC |
Post-consolidated neat PA6 as a binding matrix in CFC | N-PA6-CFC-PC |
Long carbon fibre-reinforced PA6 | L-PA6 |
Injection-moulded long carbon fibre-reinforced PA6 | L-PA6-IM |
Long carbon fibre reinforced PA6 material extruded with a raster angle of 0° | L-PA6-MEX-0° |
Long carbon fibre-reinforced PA6 as a binding matrix in CFC | L-PA6-CFC |
Post-consolidated long carbon fibre-reinforced PA6 as a binding matrix in CFC | L-PA6-CFC-PC |
Table 2.
Injection-moulded material thermal test data. Melting temperature (MT), heat deflection temperature (HDT).
Table 2.
Injection-moulded material thermal test data. Melting temperature (MT), heat deflection temperature (HDT).
Properties | Test | Unit | N-PLA | S-PLA | N-PA6 | L-PA6 |
---|
MT | ISO-11357-1:2016 | °C | 170–175 | 170–175 | 220–225 | 220–225 |
HDT | EN ISO 75-HDT A | °C | 58.0 ± 0.1 | 59.0 ± 0.2 | 48.0 ± 0.3 | -- * |
HDT | EN ISO 75-HDT C | °C | -- | -- | -- | 133.0 ± 3.0 |
Table 3.
CCF tensile test data. For the tensile test, 100 mm of CCF was taken directly from the spool, tabs were glued onto each end for gripping and to reduce damage to CCF during clamping and testing.
Table 3.
CCF tensile test data. For the tensile test, 100 mm of CCF was taken directly from the spool, tabs were glued onto each end for gripping and to reduce damage to CCF during clamping and testing.
Properties | Unit | Value |
---|
Diameter | mm | 0.36 |
Tensile strength | MPa | 2224 ± 283 |
Young’s modulus | MPa | 130000 ± 9000 |
Elongation at break | % | 1.6 ± 0.2 |
Fibre volume fraction | % | 57 |
Table 4.
Important printing settings.
Table 4.
Important printing settings.
Parameter | Unit | PLA | PA6 |
---|
CFC nozzle temperature | °C | 225 | 255 |
MEX nozzle temperature | °C | 220 | 250 |
CFC TP flow multiplier | -- | 0.95 | 1.05 |
CFC layer height | mm | 0.36 | 0.36 |
CFC extrusion width | mm | 0.75 | 0.75 |
MEX TP flow multiplier | -- | 0.90 | 1 |
MEX layer height | mm | 0.12 | 0.12 |
MEX extrusion width co-efficient | -- | 1 | 1.05 |
Bed temperature | °C | 80 | 95 |
TP perimeter count | -- | 2 | 2 |
Inner CCF perimeter count | -- | 1 | 1 |
CCF infill pattern | -- | Solid | Solid |
CCF infill angle | ° | 0 | 0 |
MEX print speed | mm·s−1 | 60 | 60 |
CFC print speed | mm·s−1 | 10 | 10 |
Table 5.
Compression pressing process conditions.
Table 5.
Compression pressing process conditions.
Setting | PLA | PA6 |
---|
Set temperature | 180 °C | 220 |
1st cooling cycle | cool down to 70 °C at 50 °C·min−1 | cool down to 150 °C at 50 °C·min−1 |
2nd cooling cycle | cool down to 23 °C at 5 °C·min−1 | cool down to 50 °C at 5 °C·min−1 |
Table 6.
Influence of rapid consolidation on void reduction in CFC specimen. For reference, the void volume fraction of the corresponding MEX specimen with a raster angle of 0° is reported.
Table 6.
Influence of rapid consolidation on void reduction in CFC specimen. For reference, the void volume fraction of the corresponding MEX specimen with a raster angle of 0° is reported.
| Void (Vol. %) |
---|
Material | MEX-0° | CFC | CFC-PC |
---|
N-PLA | 12.2 * | 14.0 | 1.0 |
S-PLA | 15.9 * | 16.3 | 8.6 |
N-PA6 | 14.3 * | 16.8 * | 8.3 |
L-PA6 | 27.0 * | 29.2 | 18.2 |